Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 4 4 2017 12 10 427 434 EN Amir Jalal Abbasi Craniomaxillofacial Research center, Tehran University of Medical Sciences, Tehran, Iran. Oral and Maxillofacial Surgery Department, School of Dentistry,Tehran University of Medical Sciences, Tehran, Iran. Naghmeh Bahrami Craniomaxillofacial Research center, Tehran University of Medical Sciences, Tehran, Iran. Oral and Maxillofacial Surgery Department, School of Dentistry,Tehran University of Medical Sciences, Tehran, Iran. Iranian Tissue Bank & Research Center, Tehran University of Medical Sciences, Tehran, Iran. Saeid Mirzaei Dentist, Craniomaxillofacial Research center, Tehran University of Medical Sciences, Tehran, Iran. 2017 12 10 2017 12 10 Objective: Good agents that can act on biologic system should be biocompatible. Biocompatible Products are the products that have the least negative effect on the body’s tissues. The aim of this study was to evaluate the in vitro tissue toxicity induced by common mini-plates used in craniomaxillofacial surgery. Materials and Methods: This study was conducted In vitro. In this study, mitochondrial coloring of living cell (MTT assay) and Annexin V/PI binding assay were measured in 5 treatments with 3 replications. to have mini plate extract, mini plates were pour in DMEM media for 30 days and used it as mini-plate extract. Experimental groups were group 1: control group (in MTT assay control group was cells treated by fresh media as negative control and incubated media as positive control and in Annexin V/PI binding assay control was cells which treated by high dose dexamethasone as positive control and cells with treated by fresh media), group 2: AO Synthes mini-plates (Tehran Arkak), group 3: General-Implants mini-plates (Behin Idea orthopedic “Biomed”), group 4: JEIL mini-plates (Pouya Teb) and group 5: Imen Ijaz mini-plates. A number of 1×104 cells was cultured on culture plate in the 96 pits for 24 and 48 hours and 7 days with each group. ANOVA test was used to compare group means. SPSS23 statistical software was used for data analysis. Results: The results of MTT assay in the time periods studied was significantly different between the studied groups (p value <0.05). The results of flowcytometry showed that the number of necrotic and apoptotic cells in experimental groups was significantly different. The maximum amount of apoptosis was seen in General mini-plate and the lowest was observed in AO Synthes and JEIL. Conclusion: The results of this study showed that the toxicity of titanium based mini-plates such as JEIL, General-Implants, Imen Ijaz and AO Synthes mini-plates had minimal toxicity and they were biocompatible. Key words: Toxicity, Mini-Plate, Titanium alloys, Apoptosis, Necrosis. https://jcr.tums.ac.ir/index.php/jcr/article/view/186 https://jcr.tums.ac.ir/index.php/jcr/article/download/186/204